This project is for the conduct of a large-scale molecular epidemiologic study, involving comprehensive mapping of highly informative DNA markers, utilizing the Cleft Lip and/or Palate (CLP) patient population at the Lancaster Cleft Palate Clinic and affiliated clinics. The role of the Lancaster Cleft Palate Clinic will be to recruit families and patients from their clinic population to participate in the study, to collect blood samples from the patients and unaffected family members recruited, and to ship the blood samples to MEDIB/EODPP for analysis. The study population will comprise: (1) members of the CLP families who participated in the original NIDR-sponsored research projects conducted in the 1960's and their descendants, (2) current patients from families with two or more affected members, and (3) additional CLP affected patients without close relatives with the disorder, as well as their unaffected close relatives as controls (a total of approximately 2,300 family members--1,150 affected and 1,150 unaffected controls).